linux-kernel - Re: [PATCH] drm/me/gsc: mei interrupt top half should be in irq disabled context

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Message-ID: <d6c4af43-0b79-4d4e-980b-0135b05da74a@lankhorst.se>
Date: Thu, 11 Dec 2025 10:42:02 +0100
From: Maarten Lankhorst <dev@...khorst.se>
To: Junxiao Chang <junxiao.chang@...el.com>, lucas.demarchi@...el.com,
 thomas.hellstrom@...ux.intel.com, rodrigo.vivi@...el.com, airlied@...il.com,
 simona@...ll.ch, bigeasy@...utronix.de, clrkwllms@...nel.org,
 rostedt@...dmis.org, daniele.ceraolospurio@...el.com,
 alexander.usyskin@...el.com, intel-xe@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 linux-rt-devel@...ts.linux.dev, Matthew Brost <matthew.brost@...el.com>
Cc: baoli.zhang@...el.com
Subject: Re: [PATCH] drm/me/gsc: mei interrupt top half should be in irq
 disabled context

Thanks for the patch, I pushed it.

I also added Matthew Brost's r-b, as I submitted this patch separately, and b4-am recognised it as the same patch.

Kind regards,
~Maarten Lankhorst

Den 2025-11-07 kl. 04:31, skrev Junxiao Chang:
> MEI GSC interrupt comes from i915 or xe driver. It has top half and
> bottom half. Top half is called from i915/xe interrupt handler. It
> should be in irq disabled context.
> 
> With RT kernel(PREEMPT_RT enabled), by default IRQ handler is in
> threaded IRQ. MEI GSC top half might be in threaded IRQ context.
> generic_handle_irq_safe API could be called from either IRQ or
> process context, it disables local IRQ then calls MEI GSC interrupt
> top half.
> 
> This change fixes B580 GPU boot issue with RT enabled.
> 
> Fixes: e02cea83d32d ("drm/xe/gsc: add Battlemage support")
> Tested-by: Baoli Zhang <baoli.zhang@...el.com>
> Signed-off-by: Junxiao Chang <junxiao.chang@...el.com>
> ---
>  drivers/gpu/drm/xe/xe_heci_gsc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_heci_gsc.c b/drivers/gpu/drm/xe/xe_heci_gsc.c
> index a415ca4887914..32d509b113915 100644
> --- a/drivers/gpu/drm/xe/xe_heci_gsc.c
> +++ b/drivers/gpu/drm/xe/xe_heci_gsc.c
> @@ -221,7 +221,7 @@ void xe_heci_gsc_irq_handler(struct xe_device *xe, u32 iir)
>  	if (xe->heci_gsc.irq < 0)
>  		return;
>  
> -	ret = generic_handle_irq(xe->heci_gsc.irq);
> +	ret = generic_handle_irq_safe(xe->heci_gsc.irq);
>  	if (ret)
>  		drm_err_ratelimited(&xe->drm, "error handling GSC irq: %d\n", ret);
>  }
> @@ -241,7 +241,7 @@ void xe_heci_csc_irq_handler(struct xe_device *xe, u32 iir)
>  	if (xe->heci_gsc.irq < 0)
>  		return;
>  
> -	ret = generic_handle_irq(xe->heci_gsc.irq);
> +	ret = generic_handle_irq_safe(xe->heci_gsc.irq);
>  	if (ret)
>  		drm_err_ratelimited(&xe->drm, "error handling GSC irq: %d\n", ret);
>  }